Stress relieving indent formation for very thin thermoformed plastic films or foil/plastic laminates

ABSTRACT

A pouch-style package formed of thin film comprising a front wall, a back wall, edge seals joining the front wall and back wall, and at least one bulge formation formed in a wall of the pouch-style package, having a stress-relieving indent formed in the wall in which said bulge formation is formed, the stress-relieving indent providing material to relieve excessive thinning or stress cracking at corners of the bulge formation.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/191,055, filed Jul. 28, 2005, and claims priority to U.S. ProvisionalPatent Application Ser. No. 60/591,623, filed Jul. 28, 2004, and U.S.Provisional Patent Application Ser. No. 60/598,064, filed Aug. 3, 2004,all of which are incorporated by reference herein.

BACKGROUND OF THE INVENTION

In the matter of pouch (sachet) style packages made of various very thinfilms, for example films of about 3 mils (0.003″) and less in thickness,in a variety of combinations such as coextruded multi-layer plastics,metal foil/thermoformable plastics, etc., it has been found that one ormore bulges can be formed in at least one of the walls of the pouch(sachet) style containment package to increase the volumetric capacityof the pouch and/or to reduce the amount of material used to contain aspecific volume, which reduces the cost significantly without much lossof barrier qualities. These bulges may be thermoformed for totallyplastic walls, or, in the case of metal foil/plastic laminatedcombinations, where the foil is very thin, for example on the order of0.0003″, air pressure forming has been the most efficient means. As amatter of fact, the pre-heating for thermoforming is detrimental forfoil/plastic combinations since it weakens the bond between the foil andthe plastic film which the foil needs for support, and the foil rupturesin numerous stress cracks when being pressure formed. It has beenfurther observed that the rounded ball corners of such bulges tend tothin out to where they also show stress cracks.

SUMMARY OF THE INVENTION

The invention is directed to a system which will relieve excessivethinning and stress cracking of such rounded ball corners. The inventionincludes the formation of one or more stress-relieving formations in thebulge formation. In certain embodiments, the stress-relieving formationis an indent in the wall of the bulge formation. In other embodiments,the stress-relieving formation is a bulge or protrusion extending fromthe bulge formation. In one example, the stress-relieving formation maybe a relatively shallow flat indented or protruded formation withsemi-circular ends in the wall of the bulge formation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a pouch (sachet) with a bulge formation with astress-relieving indent with semi-circular ends.

FIG. 2 shows another embodiment of a stress-relieving indent in the formof a channel with a semi-circular cross-section.

FIG. 3 shows another embodiment, with a plurality of stress-relievingindents.

FIG. 4 shows various shapes for stress-relieving indents, with FIG. 4Ashowing an alternative embodiment with the indent being a reverse indentor protrusion.

DETAILED DESCRIPTION OF THE DRAWINGS

A typical pouch-style package is normally rectangular. A bulge member 10may be formed in one or more walls of the pouch. These bulges with orwithout indents may be utilized in ordinary rectangular pouches ascurrently available or with various patented easy opening pouches with aflap, or with a directional tear system.

The bulge member 10 may be parallel to the edge seals 20 with ballcorners 12. In the embodiment of FIG. 1, an indent 30 with semi circularends is formed in the wall of the pouch. The tiny wall of the indentrelieves the stresses of forming the ball corners 12 by flattening out alittle when the ball corners 12 are formed.

This indent system may further be utilized to reduce stresses andthinning in various other packaging and/or other uses which requireformed thin wall systems.

It may be seen that the stress relieving indents may be of a variety ofshapes. It may further be recognized that multiple indents of various orsimilar shapes may be applied to a single unit. The concept is that theindent yields additional material when the film/foil is being formedinto a greater shape by flattening or deforming as the film isstretched, thereby yielding stress relief to the greater shape.

FIG. 2 shows another embodiment of a stress-relieving indent in the formof a channel with a semi-circular cross-section, as indicated by theline A-A′.

FIG. 3 shows another embodiment, with a plurality of stress-relievingindents, having a cross-section as indicated by the line B-B′.

FIG. 4 and FIG. 4A show various shapes for stress-relieving indents orprotrusions. The indent at C-C′ in FIG. 4 is a semi-circular indent.FIG. 4A shows an alternative embodiment, in which the semi-circularindent in FIG. 4 is a reverse indent or protrusion. As shown in FIG. 4A,the indent at C″-C′″ in such an alternative embodiment is a reverseindent or protrusion having a similar shape as the indent at C-C′. Theindent at D has a shape like a quarter-circle. The indent at E-E′ has anoblong shape. The indents at F-F′ and G-G′ are oblong in shape andcrossed.

It will be appreciated that the stress-relieving indent or protrusionmay take a variety of shapes within the scope of the claims.

1. A pouch-style package formed of thin film and containing a product tobe dispensed, the pouch-style package formed by a process comprising thesteps of: providing a first thin film comprising laminated layers ofmetal foil and plastic; providing a second thin film comprisinglaminated layers of metal foil and plastic; forming a stress-relievingindent in at least the first thin film by air pressure forming; sealingthe first thin film to the second thin film at edge seals, the edgeseals defining edges of the pouch-style package, wherein the pouch-stylepackage comprises a first wall formed of the first thin film and asecond wall formed of the second thin film, and wherein the first wallcomprises the stress-relieving indent; and forming a bulge formation insaid first wall, wherein the step of forming a bulge formation includesthe step of having the stress-relieving indent flatten or deform tofacilitate the formation of the bulge formation in said first wall.
 2. Apouch-style package as claimed in claim 1, wherein said bulge formationhas corners and wherein the stress-relieving indent provides material torelieve excessive thinning or stress cracking at corners of the bulgeformation.
 3. A pouch-style package as claimed in claim 2, wherein thecorners of the bulge formation are rounded ball corners.
 4. Apouch-style package as claimed in claim 1, wherein the indent is areverse indent so as to form a stress-relieving protrusion.
 5. Apouch-style package as claimed in claim 1, wherein the indent is arelatively shallow flat indent with semi-circular ends.
 6. A pouch-stylepackage as claimed in claim 1, wherein the indent has a semi-circularcross-section.
 7. A pouch-style package as claimed in claim 1, whereinthe indent is oblong in shape.
 8. A pouch-style package as claimed inclaim 1, wherein the step of forming a bulge formation in said firstwall takes place prior to sealing the first thin film to the second thinfilm.
 9. A pouch-style package as claimed in claim 1, wherein the stepof forming a bulge formation in said first wall takes place aftersealing the first thin film to the second thin film.
 10. A pouch-stylepackage as claimed in claim 1, wherein the stress-relieving indentprovides material to relieve excessive thinning or stress cracking inthe bulge formation.
 11. A process for forming a pouch-style packagecomprising the steps of: providing a first thin film comprisinglaminated layers of metal foil and plastic; providing a second thin filmcomprising laminated layers of metal foil and plastic; forming astress-relieving indent in at least the first thin film by air pressureforming; sealing the first thin film to the second thin film at edgeseals, the edge seals defining edges of the pouch-style package, whereinthe pouch-style package comprises a first wall formed of the first thinfilm and a second wall formed of the second thin film, and wherein thefirst wall comprises the stress-relieving indent; and forming a bulgeformation in said first wall, wherein the step of forming a bulgeformation includes the step of having the stress-relieving indentflatten or deform to facilitate the formation of the bulge formation insaid first wall.
 12. A process for forming a pouch-style package asclaimed in claim 11, wherein said bulge formation has corners andwherein the stress-relieving indent provides material to relieveexcessive thinning or stress cracking at corners of the bulge formation.13. A process for forming a pouch-style package as claimed in claim 12,wherein the corners of the bulge formation are rounded ball corners. 14.A process for forming a pouch-style package as claimed in claim 11,wherein the indent is a reverse indent so as to form a stress-relievingprotrusion.
 15. A process for forming a pouch-style package as claimedin claim 11, wherein the indent is a relatively shallow flat indent withsemi-circular ends.
 16. A process for forming a pouch-style package asclaimed in claim 11, wherein the indent has a semi-circularcross-section.
 17. A process for forming a pouch-style package asclaimed in claim 11, wherein the indent is oblong in shape.
 18. Aprocess for forming a pouch-style package as claimed in claim 11,wherein the step of forming a bulge formation in said first wall takesplace prior to sealing the first thin film to the second thin film. 19.A process for forming a pouch-style package as claimed in claim 11,wherein the step of forming a bulge formation in said first wall takesplace after sealing the first thin film to the second thin film.
 20. Aprocess for forming a pouch-style package as claimed in claim 11,wherein the stress-relieving indent provides material to relieveexcessive thinning or stress cracking in the bulge formation.